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Consumer beliefs about healthy foods and diets

That’s the title of a new article I just published in the journal PLoS ONE. This is an exploratory/descriptive study with the aim of probing consumer’s perceptions of the term “healthy” in relation to food. The study is motivated by the fact that the FDA regulates the use of the term on food packages, and is in the process of reconsidering the definition. Here are some of the key results:

Consumers were about evenly split on whether a food can be deemed healthy based solely on the foods’ nutritional content (52.1% believing as such) or whether there were other factors that affect whether a food is healthy (47.9% believing as such). Consumers were also about evenly split on whether an individual food can be considered healthy (believed by 47.9%) or whether this healthiness is instead a characteristic of one’s overall diet (believed by 52.1%). Ratings of individual food products revealed that “healthy” perceptions are comprised of at least three underlying latent dimensions related to animal origin, preservation, and freshness/processing. Focusing on individual macronutrients, perceived healthiness was generally decreasing in a food’s fat, sodium, and carbohydrate content and increasing in protein content. About 40% of consumers thought a healthy label implied they should increase consumption of the type of food bearing the label and about 15% thought the label meant they could eat all they wanted.

One part of the analysis focuses on parsing out the correlations between the healthiness rating consumers placed on different types of foods . Below are three dimensions of 15 food’s healthiness ratings as determined by factor analysis.

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Here’s the portion of the text describing these results:

The first factor (explaining 54% of the total variance), shown on the vertical axis of the bottom panel of Fig 3 shows all animal products with high values and other non-animal products with lower values, suggesting consumers use animal origin as a primary factor in judging whether a food is healthy. A second factor (explaining 31% of the total variance), illustrated on the horizontal axis of the top panel of Fig 3, has canned and frozen fruits and vegetables with the highest values, bakery and cereal items, candy, and fresh fruits and vegetables with mid-to-low values, and animal products with the lowest values, which seems to suggest consumers use degree of preservation as another dimension of healthiness. Finally, the third factor (explaining 22% of total variance), illustrated on the vertical axis of the top panel and the horizontal axis of the bottom panel of Fig 3, indicates freshness or degree of processing is another dimension to healthiness evaluations. These results indicate that healthiness is not a single unifying construct, but rather consumers evaluate healthiness along a number of different dimensions or factors. A food, such as beef or fish, can be seen as scoring high in some dimensions of healthy but low in another.

There’s a lot more in the article.

Consumer perceptions of "healthy" claims

Last week I wrote about a study I conducted on how consumers think about the word “natural.” As a part of the same project, I also delved into consumer’s perceptions of the word “healthy.”

“Healthy”, at least as a food package claim, has been defined by the FDA since 1993 by reference to total fat content, with changes made in 2016 to discriminate between different types of fat. Recently, however, the FDA has begun a process to potentially re-define the term, suggesting the need for more information on consumer’s current perceptions of the term and labeling claim.

One of the first questions on this topic I asked my sample of over 1,200 nationally representative food consumers was an open-ended question: “What does it mean to you for a food to be called ‘healthy’?” A word cloud constructed from the responses is below (the full report is available here). Words like good, fat, nutrition/nutrient/nutritional, natural, sugar, calorie, and organic were most commonly mentioned. Responses provided some support for current FDA definition as “fat” is one of the most commonly mentioned words (mentioned by 10.4% of respondents), although nearly as many (6.6%) mentioned sugar. More than a quarter of respondents provided imprecise or tautological-like definitions like “good ingredients,” “good for you,” or “healthy ingredients.”

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In addition to the open-ended question on the meaning of “healthy”, respondents were provided with a list of 13 factors that consumers might use to judge whether a food is healthy. The figure below shows that about a quarter of respondents indicated sugar content and use of hormones or antibiotics, 19.2% pointed to fat content, and 18.4% pointed to pesticide residues. The top four answers included two nutrients (sugar and fat) and two food production processes/ingredients (hormones and pesticides), suggesting consumers consider healthiness to be more than just defined by nutrient content. However, it should be noted that hormones and pesticides were infrequently mentioned (both mentioned by less than half a percent of respondents) when unaided.

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To further explore how consumers define and think about healthiness, a couple binary choice questions were posed. Consumers were about evenly split on whether a food can be deemed healthy based solely on the foods’ nutritional content (52.1% believing as such) or whether there were other factors that affect whether a food is healthy (47.9% believing as such). Consumers were also evenly split on whether an individual food can be considered healthy (believed by 47.9%) or whether this healthiness is instead a characteristic of one’s overall diet and the combination of foods consumed (believed by 52.1%). These responses suggests difficulty in creating a definition of “healthy” on food packages that is broadly acceptable to consumers. Answers to these two questions are not determinative of each other, but rather there are four distinct consumer segments with regard to healthy food conceptions. The figure below indicating the percent of respondents who answered these two questions in the four possible manners.

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Respondents were also provided a list of 15 foods in random order and were asked to indicate whether each was healthy, unhealthy, or neither healthy nor unhealthy. For each item, a healthiness score was created by subtracting the percent of respondents who considered a process unhealthy from the percent of respondents who considered a process healthy. The figure below shows the results.

Almost all respondents (96.2%) considered fresh vegetables to be healthy, and almost none (0.9%) considered them unhealthy, yielding a net healthy score of 96.2-0.9=95.3% for fresh vegetables. Fresh fruit, fish, eggs, and chicken were likewise broadly considered healthier than not. Frozen vegetables/fruit were considered less healthy than fresh, and canned were considered less healthy than frozen, although even canned was considered, on net, more healthy than unhealthy. Only three of the 15 items listed were considered by more respondents to be unhealthy than healthy: vegetable oil, bakery and cereal items, and particularly candy.

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To explore how consumers conceptualized the healthiness of different foods, the questions used to create the figure above were further analyzed using factor analysis. The first factor, shown on the vertical axis of the following figure shows all animal products with high values and other non-animal products with lower values, suggesting consumers use animal origin as a primary factor in judging whether a food is healthy. Another factor illustrated on the vertical axis, indicates freshness or degree of processing is another dimension to healthiness evaluations. These results indicate that healthiness is not a single unifying construct, but rather consumers evaluate healthiness along a number of different dimensions or factors. A food, such as beef or fish, can be seen as scoring high in some dimensions of healthy but low in another.

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Respondents were asked to indicate their extent of agreement or disagreement with eight statements. The highest levels of agreement were with the statement, “Individual needs determine whether various foods are healthy for an individual.” Only 7.8% of respondents disagreed with this statement, whereas more than 70% agreed with it. There were also strong beliefs that healthy food is safe to eat and natural. There was only moderate agreement that healthier food is tastier. About 44% of respondents neither agreed nor disagreed with this statement. There was slightly more disagreement than agreement that healthy food is more convenient to eat. A majority of consumers (58%) disagreed that healthy is more affordable.

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There is a lot more in the full report.

Trends in National School Lunch Program

Back in 2010, the U.S. Congress passed the Healthy, Hunger-Free Kids Act. The Act, championed by Michelle Obama, provided funding for free and reduced price school lunches and breakfasts, introduced a variety of new nutritional guidelines, and provided incentives for schools to offer healthier options.

The law went into effect at the beginning of the 2012-2013 academic year. There was a fair amount of initial push back. A video from these Kansas students protesting the calorie restrictions has been viewed more than a million times, and other students took to social media with photos of the new lunches using the hashtag #ThanksMichelleObama. This CNN article from 2017 provides some background and also reports on the efforts of a large school food service industry association to roll back some of the guidelines.

The new guidelines may well have generated some positive health benefits for students who ate school lunches. But, how have these policies potentially affected participation in the National School Lunch Program (NSLP)? Students are not required to eat the school-provided NSLP lunches. Students can bring food from home, go off campus, or find other substitutes at school.

I downloaded some data from the US Department of Agriculture (USDA), Food and Nutrition Service (FNS). These data show that in 2017, 4.89 billion lunches were served under the NSLP, with 73.6% being free or reduced price and the remaining 26.4% of students paying full price. How have these statistics changed over time?

As the figure below shows, there was a nearly linear increase in the number of lunches served each year in the NSLP right up until 2010, after which there was a slowdown and then a slow decline.

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The effects can be seen even more dramatically by converting the data in the above figure to annual percentage changes in the number of NSLP meals served. From 1990 to 2008, the school lunch program grew every year. Since 2011, the program has gotten smaller every year except in 2016. In the six years prior to the law’s enactment in 2010, there was an average annual increase of 1.4% in the number of NSLP meals served, but in the six years since the law’s enactment (from 2012 to 2017), there was an annual average decrease of -1.2% in the number of NSLP meals served.

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The data also suggest another interesting dynamic at play. Below is the percent of NSLP meals that are free or reduced priced. Throughout most of the 2000’s just under 60% of NSLP meals were free or reduced price. Since then, there has been a fairly steady increase in the share of meals that are subsidized. Given that the increase started prior to the enactment of the 2010 Healthy Hunger-Free Kids Act, it is likely that other factors (such as the Great Recession) were playing a role. However, there has continued to be an increase in the share of NSLP meals that are free or reduced price well after the recession ended.

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These data show there are fewer meals being served that fall under the National School Lunch Program umbrella and that students who pay full price have increasingly chose to eat meals not governed by the program.

The figures presented above do not causality prove that the 2010 Healthy, Hungry-Free Kids Act led to the decline in the meals served under the USDA National School Lunch Program, but they are interesting trends about which I was previously unaware.

Diet quality, environmental impacts, and food waste

A few years ago when the federal dietary guidelines were being discussed, there seemed to be a growing consensus that nutritional goals and sustainable goals could be jointly achieved with a single diet.  I pushed back some on that at the time (e.g., see here or here).

I ran across this paper by Zach Conrad and colleagues that was just published in PLoS ONE.  The paper shows that there is unlikely to be a silver bullet diet free of trade-offs when multiple dimensions of comparison are involved.  Here's from the abstract:  

Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary.

Understanding the Impacts of Food Consumer Choice and Food Policy Outcomes

The journal Applied Economics Perspectives and Policy just published a special issue in which  agricultural and applied economists provide their thoughts on how we might help tackle some of society’s most difficult problems and challenges.  I co-authored one of the articles with Jill McCluskey.  Here's the abstract:

The food consumer plays an increasingly prominent role in shaping the food and farming system. A better understanding of how public policies affect consumer choice and how those choices impact health, environment, and food security outcomes is needed. This paper addresses several key challenges we see for the future, including issues related to dietary-related diseases and the efficacy of policies designed to improve dietary choices, trust in the food system, acceptance of new food and farm technologies, environmental impacts of food consumption, preferences for increased food quality, and issues related to food safety. We also identify some research challenges and barriers that exist when studying these issues, including data quality and availability, uncertainty in the underlying biological and physical sciences, and the challenges to welfare economics that are presented by behavioral economics. We also identify the unique role that economists can play in helping address these key societal challenges.

Other contributions in the special issue include:

  • "Agricultural and Applied Economics Priorities for Solving Societal Challenges" by Jill McCluskey, Gene Nelson, and Caron Gala
  • "Economics of Sustainable Development and the Bioeconomy" by David Zilberman, Ben Gordon, Gal Hochman, Justus Wesseler
  • "Sustaining our Natural Resources in the Face of Increasing Societal Demands on Agriculture: Directions for Future Research" by Madhu Khanna, Scott Swinton, Kent D Messer
  • "Climate Change as an Agricultural Economics Research Topic" by Bruce McCarl and Tom Hertel
  • "Big Data in Agriculture: A Challenge for the Future" by Keith Coble, Ashok Mishra, Shannon Ferrell, and Terry Griffin
  • "The Economic Status of Rural America in the President Trump Era and beyond" by Stephan Goetz, Mark Partridge, Heather Stephens
  • "Food Insecurity Research in the United States: Where We Have Been and Where We Need to Go" by Craig Gundersen and James Ziliak
  • "The Farm Economy: Future Research and Education Priorities" by Allen Featherstone
  • "A Research Agenda for International Agricultural Trade" by Will Martin
  • "Energy Economics" by Wally Tyner, and Nisal Herath